LIBAWS++ is an open-source (Apache 2.0 License) C++ library for interfacing with AWS. Specifically, the library currently supports interaction with S3, SQS, and SDB. The library is tested on Linux and Mac OS X and works very well for us. Moreover, it comes with two additional cool tools:

1. three command-line clients for each of the services mentioned above. For example, the S3 command line utility allows you to create buckets, list objects, or delete objects.

2. we've also created a fuse-based filesystem for S3. It works on Linux (with libfuse) and Mac (with MacFuse). Moreover, it can be compiled with Memcache support allowing caching of meta-data.